Non-volatile storage elements may include a dielectric barrier layer, typically made of silicon dioxide, sandwiched between two electrode layers, such as two metal layers or two layers of polysilicon. A voltage may be applied to a first electrode layer (typically a top electrode layer) of the two electrode layers to control write and erase operations. Specifically, when a voltage is applied to the first electrode layer, charges move past the barrier layer and into a second electrode by way of well known tunneling or hot carrier injection mechanisms.
Currently, storage elements that require long data retention in the off-state are constructed with thick barrier layers, typically in the order of 70 Angstroms, in order to prevent any stored charges from leaking. As a result, higher voltages may need to be applied to the first electrode layer as compared with a situation where the barrier layer was thinner. Conversely, to achieve a low voltage operation, the barrier layer may be thinned in order to allow easier charge injection into the second electrode. However, a thinner barrier layer may result in stored charges from leaking more easily through the barrier, reducing the lifetime of the storage element.